VALENCIA, SPAIN - NOVEMBER 30: Neymar of FC Barcelona competes for the ball with Otamendi of Valencia CF during the La Liga match between Valencia CF and FC Barcelona at Estadi de Mestalla on November 30, 2014 in Valencia, Spain. (Photo by Miguel Ruiz/FC Barcelona via Getty Images)

VALENCIA, SPAIN - NOVEMBER 30: Lionel Messi (3dL) of FC Barcelona competes for the ball with Shkodran Mustafi (2ndR) of Valencia CF and his teammate Javier Fuego (R) during the La Liga match between Valencia CF and FC Barcelona at Estadi de Mestalla on November 30, 2014 in Valencia, Spain. (Photo by Gonzalo Arroyo Moreno/Getty Images)

VALENCIA, SPAIN - NOVEMBER 30: Sergio Busquets Burgos (L) of FC Barcelona celebrates his opening goal with team mate Neymar JR. (2ndL) as goalkeeper Diego Alves (2ndR) lies on the ground close to his teammate Jose Gaya (R) during the La Liga match between Valencia CF and FC Barcelona at Estadi de Mestalla on November 30, 2014 in Valencia, Spain. (Photo by Gonzalo Arroyo Moreno/Getty Images)

VALENCIA, SPAIN - NOVEMBER 30: Shkodran Mustafi (L) of Valencia CF competes for the ball with Neymar JR. (R) of FC Barcelona during the La Liga match between Valencia CF and FC Barcelona at Estadi de Mestalla on November 30, 2014 in Valencia, Spain. (Photo by Gonzalo Arroyo Moreno/Getty Images)

Following Sunday's Valencia vs. Barcelona match, which ended in a 0-1 victory for Barcelona after a late-in-the-game goal, fans seem to be focusing on one moment in particular: When Barcelona's Neymar appeared to headbutt Argentine defender Nicolás Otamendi as he bent down to remonstrate with the Brazilian.

Footage shows Otamendi approaching Neymar and placing his right hand behind the Brazilian's head before Neymar appears to jut his head towards the defender's jaw, in what some are calling 'the world's worst headbutt.'

Otamendi fell back in dramatic fashion before players from both sides erupted in argument, while Neymar went unpunished from referee David Fernández.